This invention relates generally to a method for winding coils on a Y-connection armature for miniature motors, and more particularly to a method for winding coils on a Y-connection armature for miniature motors, which leads itself to simplification of the process for winding coils on a Y-connection armature and improvement of production efficiency.
FIG. 1 is a longitudinal sectional view illustrating the essential part of a miniature motor to which this invention is applied. In FIG. 1, reference numeral 21 refers to a motor housing, made of a magnetic material, such as mild steel, formed into a deep cup shape, a field magnet 22 is fixedly fitted to the inner circumferential surface of the motor housing 21. Numeral 23 refers to an end plate, fitted to an open end of the motor housing 21. Numeral 24 refers to an armature comprising an armature iron core 2, a commutator 5, and an armature shaft 1 fixedly fitted to the axial center thereof. Numerals 25 and 26 refer to bearings provided on the motor housing 21 and the end plate 23 to rotatably support the armature shaft 1. Numeral 27 refers to a terminal provided on the end plate 23. Numeral 28 refers to a brush electrically connected to the terminal 27, and formed in such a manner as to make sliding contact with the commutator 5.
With this construction, as electric current is fed from the terminal 27 to the armature via the brushes 28 and the commutator 5, the armature 24 disposed in a magnetic field formed by the field magnet 22 fixedly fitted to the inner circumferential surface of the motor housing 21 is caused to rotate.
FIGS. 2 and 3 are a side view and an enlarged longitudinal sectional side view illustrating the armature shown in FIG. 1. In FIGS. 2 and 3, numeral 2 refers to an armature iron core comprising three armature poles 7 and an armature shaft fixedly fitted to the axial center thereof; numeral 4 to an insulating cylinder fixedly fitted to an end of the armature shaft 1; numeral 5 to a commutator having three tongues 6 on the outer circumferential surface thereof and fixedly fitted to the outer circumferential surface of the insulating cylinder 4; numeral 10 to a common terminal plate having three tongues 11 on the outer circumferential surface thereof and fixedly fitted to the outer circumferential surface of the insulating cylinder 4 via an insulating ring-shaped member 12. The tongues 6 and 11 should preferably be disposed at essentially the same circumferential and axial positions.
Numeral 9 refers to a coil wound in a slot 3 formed on the armature iron core 2. An end of a lead wire 8 is connected to the tongue 6 of the commutator 5 and the other end thereof is connected to the tongue 11 of the common terminal plate 10 to form a Y-connection armature.
FIG. 4 is a development of assistance in explaining the conventional method for winding coils on a Y-connection armature. Like parts are indicated by like numerals in FIGS. 2 and 3. In FIG. 4, 71, 72 and 73 refer to armature poles disposed at 120-degree intervals with each other to form an armature iron core 2 in FIGS. 2 and 3. Numerals 61, 62 and 63 refer to tongues, representing the positions at which the tongues 6 of the armature 5 in FIGS. 2 and 3 are disposed. Numerals 111, 112 and 113 refer to tongues, representing the positions at which the tongues 11 provided on the common terminal plate 10 in FIGS. 2 and 3 are disposed. The tongues 61-63, and 111-113 are disposed at 120-degree intervals with each other, as in the case of the armature poles 71-73.
With the above-mentioned construction, a conventional method for winding coils on the Y-connection armature will be described. A first coil 91 is wound by connecting a trailing end of the lead wire 8 to the first tongue 61, then winding the lead wire 8 on the first armature pole 71 to form the first coil 91, and connecting the trailing end of the lead wire 8 to the first tongue 111 of the common terminal plate 10. After the terminal wire 8 is connected to the tongues 61 and 111 the lead wire 8 is subjected to the wire-end termination (a wire end termination procedure). Although only one turn of the first coil 91 is shown in FIG. 4 for simplicity, the coil 91 has a predetermined number of turns. This holds true with the second and third coils 92 and 93.
When winding the second and third coils 92 and 93, ends of the lead wires 8 are wound on the second and third armature poles 72 and 73 to form the second and third coils 92 and 93, and the other ends, that is, the trailing ends of the lead wires 8 are connected to the second and third tongues 112 and 113 of the common terminal plate 10.
In the conventional method for winding coils on a Y-connection armature as described above, the wire-end termination treatment has to be performed on the leading and trailing ends of the lead wire 8 every time one coil is formed.
That is, two wire-end terminations are needed for one coil. Consequently, 2N times of wire-end terminations are needed for N pieces of coils wound on a Y-connection armature.
Since the conventional method for winding coils on a Y-connection armature requires multiple wire-end terminations, as described above, coil winding is time consuming, requires complex winding operations, leading to lower production efficiency. This also results in increased motor cost.